1. Field of the Invention
The present invention relates to a semiconductor device and a manufacturing method of the semiconductor device.
2. Description of the Related Art
Conventionally, a semiconductor device which is equipped with a thin film inductor having a spiral form, referred to as a chip size package (CSP), has been known. Such semiconductor device is disclosed, for example, in Japanese Patent Application Laid-open Publication No. 2008-210828. This semiconductor device comprises a semiconductor substrate. An insulation film is provided on an upper surface of the semiconductor substrate. A plurality of wires and the thin film inductor having the spiral form are provided on an upper surface of the insulation film. A columnar electrode is provided on an upper surface of a connection pad portion of the wires. A sealing film is provided in a state of surrounding the columnar electrode. A solder ball is provided on an upper surface of the columnar electrode.
In such semiconductor device described above, the insulation film comprises a passivation film formed of oxide silicon, and the like, provided on the upper surface of the semiconductor substrate; and a protection film formed of polyimide system resin, and the like, provided on an upper surface of the passivation film. In a case where the wires and the thin film inductor are provided on an upper surface of the protection film, an eddy current is generated in the semiconductor substrate by an induction when a current flows through the wires. Then, an eddy-current loss is generated in the thin film inductor due to the generated eddy current, thereby the property of the thin film inductor is to be degraded.
In order to solve the above mentioned problem, in the semiconductor device disclosed in Japanese Patent Application Laid-open Publication No. 2008-210828, a magnetic film which is formed by mixing soft magnetic powder into a thermosetting resin made of polyimide system resin, and the like, is provided in stead of the protection film formed of the polyimide system resin, and the like, in between the passivation film and the thin film inductor placed on or above the semiconductor substrate. Accordingly, the eddy-current loss of the thin film inductor due to the eddy current generated in the semiconductor substrate is intended to be reduced.
However, in the above described semiconductor device, the magnetic film is manufactured by mixing the soft magnetic power which is a relatively expensive material into the thermosetting resin made of polyimide system resin, and the like, thereby the semiconductor device results in also being relatively expensive. Further, it is difficult to disperse the soft magnetic powder evenly into the thermosetting resin. Here, a circuit may be shunted at a portion where the soft magnetic powder is densely dispersed. On the other hand, the effect of the eddy-current loss being reduced may be deteriorated at a portion where the soft magnetic powder is scarcely dispersed.